From: Alexei Starovoitov <ast@xxxxxxxxxx>
Make -d flag functional for gen_loader style program loading.
For example:
$ bpftool prog load -L -d test_d_path.o
... // will print:
libbpf: loading ./test_d_path.o
libbpf: elf: section(3) fentry/security_inode_getattr, size 280, link 0, flags 6, type=1
...
libbpf: prog 'prog_close': found data map 0 (test_d_p.bss, sec 7, off 0) for insn 30
libbpf: gen: load_btf: size 5376
libbpf: gen: map_create: test_d_p.bss idx 0 type 2 value_type_id 118
libbpf: map 'test_d_p.bss': created successfully, fd=0
libbpf: gen: map_update_elem: idx 0
libbpf: sec 'fentry/filp_close': found 1 CO-RE relocations
libbpf: record_relo_core: prog 1 insn[15] struct file 0:1 final insn_idx 15
libbpf: gen: prog_load: type 26 insns_cnt 35 progi_idx 0
libbpf: gen: find_attach_tgt security_inode_getattr 12
libbpf: gen: prog_load: type 26 insns_cnt 37 progi_idx 1
libbpf: gen: find_attach_tgt filp_close 12
libbpf: gen: finish 0
... // at this point libbpf finished generating loader program
0: (bf) r6 = r1
1: (bf) r1 = r10
2: (07) r1 += -136
3: (b7) r2 = 136
4: (b7) r3 = 0
5: (85) call bpf_probe_read_kernel#113
6: (05) goto pc+104
... // this is the assembly dump of the loader program
390: (63) *(u32 *)(r6 +44) = r0
391: (18) r1 = map[idx:0]+5584
393: (61) r0 = *(u32 *)(r1 +0)
394: (63) *(u32 *)(r6 +24) = r0
395: (b7) r0 = 0
396: (95) exit
err 0 // the loader program was loaded and executed successfully
(null)
func#0 @0
... // CO-RE in the kernel logs:
CO-RE relocating STRUCT file: found target candidate [500]
prog '': relo #0: kind <byte_off> (0), spec is [8] STRUCT file.f_path (0:1 @ offset 16)
prog '': relo #0: matching candidate #0 [500] STRUCT file.f_path (0:1 @ offset 16)
prog '': relo #0: patched insn #15 (ALU/ALU64) imm 16 -> 16
vmlinux_cand_cache:[11]file(500),
module_cand_cache:
... // verifier logs when it was checking test_d_path.o program:
R1 type=ctx expected=fp
0: R1=ctx(id=0,off=0,imm=0) R10=fp0
; int BPF_PROG(prog_close, struct file *file, void *id)
0: (79) r6 = *(u64 *)(r1 +0)
func 'filp_close' arg0 has btf_id 500 type STRUCT 'file'
1: R1=ctx(id=0,off=0,imm=0) R6_w=ptr_file(id=0,off=0,imm=0) R10=fp0
; pid_t pid = bpf_get_current_pid_tgid() >> 32;
1: (85) call bpf_get_current_pid_tgid#14
... // if there are multiple programs being loaded by the loader program
... // only the last program in the elf file will be printed, since
... // the same verifier log_buf is used for all PROG_LOAD commands.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
tools/bpf/bpftool/prog.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index e47e8b06cc3d..b9f42e9e9067 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1779,12 +1779,14 @@ static int try_loader(struct gen_loader_opts *gen)
ctx = alloca(ctx_sz);
memset(ctx, 0, ctx_sz);
ctx->sz = ctx_sz;
- ctx->log_level = 1;
- ctx->log_size = log_buf_sz;
- log_buf = malloc(log_buf_sz);
- if (!log_buf)
- return -ENOMEM;
- ctx->log_buf = (long) log_buf;
+ if (verifier_logs) {
+ ctx->log_level = 1 + 2 + 4;
+ ctx->log_size = log_buf_sz;
+ log_buf = malloc(log_buf_sz);
+ if (!log_buf)
+ return -ENOMEM;
+ ctx->log_buf = (long) log_buf;
+ }
opts.ctx = ctx;
opts.data = gen->data;
opts.data_sz = gen->data_sz;
@@ -1793,9 +1795,9 @@ static int try_loader(struct gen_loader_opts *gen)
fds_before = count_open_fds();
err = bpf_load_and_run(&opts);
fd_delta = count_open_fds() - fds_before;
- if (err < 0) {
+ if (err < 0 || verifier_logs) {
fprintf(stderr, "err %d\n%s\n%s", err, opts.errstr, log_buf);
- if (fd_delta)
+ if (fd_delta && err < 0)
fprintf(stderr, "loader prog leaked %d FDs\n",
fd_delta);
}
--
2.30.2
